Transparent cutting oil containing active sulfur and sulfochlorinated mono-olefin polymer



ice content-ofjhighly active sulfur, but this results in a dark I TRANSPARENT CUTTING OIL CONTAINING AC- TIVE SULFUR AND SULFOCHLORINATED MONO-QLEFIN POLYMER Richard Givens, Port Arthur, Tex., assignor to The a Texas Company, New York, N. Y., a corporation of Delaware Nd Drawing. Application June 23, 1951, Serial No. 233,262

2 Claims. (Cl. 252-483) This invention relates to a light colored or transparent cutting oil; of the heavy duty type, and particularly to such an oil having a mineral lubricating oil base and containing the combination of both added active free sulfur and a sulfo-chlorinated mono-olefin polymer.

" it well recognized that cutting oils for heavy duty be prepared by sulfun'zing mineral lubricating ride rigorous conditions to provide a substantial paque oil which hides the work from the view .e'rator during the cutting operation. Also, so-

called traitisparent cutting oils have been produced by mildly sulfurizing mineral lubricating oil at temperatures ;ofab.out290 340 F. and at atmospheric presure to inwork. With the advent of improved harder alloys and higher cutting speeds in various precision cutting operations, the need for a truly transparent cutting oil of the heavy duty type which is substantially equivalent in cutting efficiency to the dark colored opaque oils has been emphasized.

A principal object of the present invention is to provide a transparent cutting oil of the heavy duty type employing a mineral lubricating oil base which approaches or substantially equals in cutting efiiciency the previously used dark colored opaque oils.

A further object of the present invention is to produce such a transparent cutting oil of the heavy duty type while avoiding the use of expensive solvents or chemicals, whereby an economical product of superior quality is afiorded.

In accordance with the present invention, the foregoing objects have been attained by incorporating in a refined mineral lubricating oil distillate of the character of a socalled pale oil, the combination of about 0.4-0.95% by weight of added active free sulfur, together with about 0.75-5% by weight of a sulfa-chlorinated mono-olefinic polymer having a substantial content of both .combined chlorine and combined sulfur. It has been found that there is a cooperative or synergistic effect between these combined additives, with the net result that the transparent cutting oil provides superior performance in actual full scale cutting operations over transparent cutting oils heretofore available, and closely aproaches if not equals the cutting effectiveness of the heavy duty opaque oils. At the same time, the cutting oil of the present invention possesses a high transparency as represented by a light color on the Lovibond scale /2 in. cell) below 85 The mineral lubricating oil employed as the base, and which constitutes at least about 95% by weight of the nited States Patent 9f bined chlorine and 10-25% by weight of combined sulfur.

p 2,786,031 Patented Mar. 19, 1957 ice composition, is a refined treated pressed distillate or dewaxed distillate, which is finished by stilling, light to moderate acid treating, neutralizing, steaming and brightening. A parafiin base oil is generally preferred. The oil has an SUS Viscosity at F. of 100-200, and preferably about -170.

The added active free sulfur is introduced into the base oil by heating the latter with about 0.40.95% by weight of powdered sulfur at a temperature of about 290340 F. for about to 1 /2 hours, and preferably at a temperat-ure of around 315 F. for about 1 hour. The sulfur is believed to be mainly in solution in the oil, although it may be in a loosely combined form, such that the total added sulfur is in a highly active state. The amount of added sulfur is preferable toward the upper end of the aforesaid range, generally about 0.7-0.9% and approaches the limit of solubility of the sulfur in the particular base oil employed.

The introduction of the sulfur into the base oil can be accomplished by a batch treatment, or can be done in a continuous manner involving a pipe coil heating operation. The base oil with the added active sulfur preferably has a color on the Lovibond scale /2 in. cell) below about 40, and generally about 25-35, so that further darkening of the product upon the incorporation of the sulfochlorinated polymer will not raise the color of the finished oil above about 8085, and preferably will be about 60 or lower. Following the sulfurizat-ion at the elevated temperature, the resulting oil is allowed to cool to about F. or lower, and then air is bubbled through the oil or the latter is steam stripped under vacuum to remove HzS until the sulfurized oil is no more than faintly positive to the lead acetate test. The sulfurized oil is then allowed to settle and the clear oil decanted. The sulfo-chlorinated polymer is added to the clear sulfurized oil at substantially room temperature.

The mono-olefinic polymers which are sulfo-chlorinated are those of the lower molecular weight olefins having less than 6 carbon atoms in the molecule, and include the liquid polymers of ethylene, propylene, the butylenes and the amylenes. butylene and triisobutylene, are preferred. While the liquid polymers may be prepared from a single olefin, such as isobutylene, the copolymers formed by the polymerization of a mixture of two or more of the said lower molecular weight olefins, can also be employed. The polymerization is carried out in conventional manner in the presence of well-known catalysts, such as BFa, solid phosphoric acid, aluminum chloride, sulfuric acid and the like. As hereinbefore stated, the polymerization is terminated before the resinous stage and while the polymers are liquid when cool.

The sulfo-chlorination of the resultant polymers is conveniently accomplished by reacting the same with about 40-50% by weight of sulfur mono-chloride without added heat, followed by subsequent stabilization of the reaction product by heat treatment at temperatures of about 300350 F. This is followed by neutralization of any strong acidity so that the product passes the copper strip corrosion test at 122 F., the neutralization being conveniently accomplished by passing the sulfo-chlorinated polymer in contact with marble chips. In order to incorporate a higher proportion of chlorine with respect to sulfur in the polymer, the latter may be first chlorinated as by bubbling chlorine gas through material at 150 F., and the resulting chlorinated product subsequently treated with about 30-50% of sulfur monochloride and stabilized in the foregoing manner. The resulting sulfo-chlorinated mono-olefin polymers of this type generally contain about 15-30% by weight of com? A preferred material of this class is sulfo-chlorinated The isobutylene polymers, such as diisodiisobutylene containing about 19-22% of combined sulfur and 2225% of combined chlorine. Another suitable material of this type is. sulfo-chlorinated triisobutylene having approximately 14-17% of combined sulfur and about 1922% of combined chlorine. Anglamol 35 sold by the Lubrizol Corporation is representative of a commercially available material which is eminently satisfactory for purposes of the present invention, and 1s a sulfo-chlorinated diisobutylene containing 23-25% of combined chlorine and 19-22% of combined sulfur. Both the sulfur and chlorine are stably combined and the product is non-corrosive in the copper strip corrosion test at 122 F. such as to produce no blackening of the copper strip in 6 hours.

The sulfo-chlorinated polymer is added to the base oil in a proportion to provide about 0.75% by weight on the basis of the finished cutting oil, and preferably about 1.25-2.0% from the standpoint of color and cost. The addition is made by stirring the sulfurized base oil with the required amount of sulfo-chlorinated polymer at substantially atmospheric temperature, although it can be added at a mildly elevated temperature below about 150 F. While these sulfo-chlorinated mono-olefinic polymers are known extreme pressure agents, it was not to be anticipated that this type of material in combination with the added active free sulfur in the base mineral oil would provide a cutting oil having both the high transparency and the superior cutting efficiency in actual cutting operations. This is especially true since other known types of sulfo-chlorinated extreme pressure agents, such as sulfo-chlorinated fatty oils, failed to satisfy these requirements. Thus the sulfo-chlorinated fatty oils either produce darkening of the cutting oil so that transparency is lost, or else do not give the synergistic effect with the added active free sulfur such that the cutting properties are inferior.

The following examples are given in order to illustrate the present invention:

Example 1 A blend of 480 pounds of a refined paralfin base pale oil having an SUS viscosity at 100 F. of 230 with 320 pounds of a refined parafl'in base pale oil havingv an SUS viscosity at 100 F. of 108.8 was charged to' a steam heated kettle equipped with a stirrer. During heating of the kettle contents up to a temperature of 320 F., 27.7 pounds of the blend was removed to prevent overflow, leaving 773.3 pounds of the blend to be sulfurized. At this temperature of 320 F., 6.24 pounds of sulfur were slowly added with stirring, and the temperature was maintained at 310-320 F. for one hour. The steam to the kettle was then cut off, and cooling water supplied to the kettle jacket to cool the sulfurized oil down to a temperature of 150 F. in one hour. A control sample of the sulfurized oil had a color of 25 on the Lovibond scale cell) and an, SUS viscosity of 100 F. of 166. Air was then bubbled through the batch in the kettle for 3 /2 hours, until the latter was only slightly positive to the lead acetate test and a sample had a color on, the Lovibond scale /2" cell) of 35. The batch was then allowed to stand until it cooled to room temperature and was then filtered through cheese cloth.

248.3 pounds of the foregoing sulfurized pale oil was charged to a kettle together with 11.7 pounds of a cutback consisting of a /3 part by weight of Anglamol and /srds part by weight of a paraffin base lubricating oil distillate having an SUS viscosity at 100 F. of 230. The kettle contents were stirred for minutes at room temperature. The resulting product which was a clear straw-colored mobile oil was then pumped to tankage and allowed to stand in quiescent condition for a period of about five weeks. will occur in .this period, and the supernatant clear oilis thenstable in subsequent storage and. use. The fore- It is found that any sedimentation.

going finished oil had the following calculated composition:

Percent by wt. Pale oil 97.74 Added active free sulfur 0.76 Anglamol 35 1.5

The foregoing Anglamol 35 tested 21.57% by weight of combined sulfur and 23.8% of combined chlorine. The following tests were obtained on the above finished oil:

Gravity API 26.1 Flash, 0. Cleve, F 390 Fire, Cleve, F g 455 SUS Vis. at 100 F 170;-7 Color, Lovi. /2 cell Carbon residue, percent 0.15 Total sulfur, percent 1.25 Cold test at 2530 for 60 hours 1 O. K.

SAE extreme pressure, 1000 R. P. M.-lbs 166, 161, 152

1 No sedimentation.

Example 2 A series of transparent cutting oils were prepared in the manner of Example 1 above, but employing different proportions of Anglamol 35. Tests obtained on these oils are set forth in the following Table II:

sulfurized Color Lovi- SAE Test, Base 011+ bond, in. 1,000 Additive, percell R. P. M., lbs.

cent by wt. I

1 Also eontains 1% tricresyl phosphate.

Samples 1, 5, 9 and 15 of the above table represent dilferent batches of sulfurizedbase oil which may vary materially in SAE value as shown. The samples immediately following each base oil were prepared from that particular batch. Samples 2-4 inclusive also contained 1% by weight of tricresyl phosphate in the formulation. Comparison of samples 3 and 7 indicates that tricresyl phosphate is not compatible with the sulfo-chlorinated polymer in this type of cutting oil and is desirably omitted from the formulation. Samples 8 and 14 show that 5% of the sulfo-chlorinated polymer represents about the upper limit in order to obtain the desired transparency and color.

Example 3 The transparent cutting oil of Example 1 above was subjected to field tests in a push rod threading operation in comparison with the previously known type of transparent cutting oil containing tricresyl phosphate, and with a dark colored highly sulfurized heavy duty cutting oil of known superior cutting properties. The operation "750 for the dark colored heavy duty cutting oil. Thus the cutting oil of the present invention more than doubled the prior output with a transparent cutting oil, and approached in cutting effectiveness the output of an opaque heavy duty cutting oil that prevented the work from being visually observed.

Example 4 The {transparent cutting oil of Example 1 above was cut back 50% with pale oil to provide a product having approximately 0.4% of added free active sulfur and 0.75% of Anglamol 35. This cutting oil was subjected to field treated'steel in comparison with the opaque type of highly isu lfurized heavy duty cutting oil. The operation was ..carried .out on a Landis Double Head Threading Machine tests in 'a threading operation on No. 4140 heat cutting in. No. 11 pitch threads throughout a length i of 13 on each of the steel bars at a spindle speed o 5 P M, and a surface speed of 65 feet per The transparent cutting oil of the present invention gave an average of 19 bars satisfactorily threaded before the chasers required removal for regrinding, in comparison to an average of 18 bars for the dark colored heavy duty oil.

Example 5 The cutting oil of Example 1 above was subjected to field tests in a hobbing operation in comparison with both the previously used type of transparent cutting oil containing tricresyl phosphate, and the dark colored highly sulfurized heavy duty type of cutting oil. This operation involved use of a Barber-Coleman Hobber cutting ten SAE 4027 steel spur gears at a time at a speed of 165 feet per minute on a 6 in. diameter 5 thread hob. In a five months test, the transparent cutting oil of the present invention Was rated comparable to the dark colored heavy duty cutting oil, while the previously known transparent cutting oil was found to be incapable of satisfactorily handling this severe cutting operation.

Example 6 The following illustrates continuous manufacture of the cutting oil of the present invention. A pale oil blend having an SUS viscosity at 100 F. of 125-130 for a lighter grade and 160-165 for a heavier grade was charged to a heater and reactor unit consisting of a pipe coil heater and tank with recirculating pump. After this system was filled with approximately 120 bbls. of the pale oil blend, the contents were recirculated in the system at the rate of 50 bbls. per hour until the outlet temperature of the reactor had been raised to 325-335 F. Sulfur was then added to the oil in the system at the rate of 125 pounds per hour, while recirculating was continued and the reactor outlet temperature maintained at 325-335 F., until a quantity of sulfur suflicient to provide 0.8% by weight based on the final composition and represented by the oil then in the system had been added. At this time, recirculation was stopped and a continuous operation involving pumping the oil through the heater and reactor and then discharging was initiated. With the charge pump set for 50 bbls. per hour, sulfur was injected into the charge oil at the rate of 125 pounds of sulfur per hour, while both the preheater and reactor outlet temperatures were maintained at 325-335 F. The oil required about 45-60 min. to traverse this system.

The sulfurized oil was discharged into a previously evacuated vacuum tower into which steam was injected to remove HzS. The oil from the tower then passed through a cooler maintained at an outlet temperature of 120-140 F. to a large finishing tank. Then 1.5% by weight of Angl-amol 35 (or 4.5% of the cutback of Anglamol 35 containing twice its weight of pale oil) was added and blended by air blowing for about 30 min. The resulting cutting oil was then allowed to stand in tankage for about 5 weeks, and the supernatant oil was then filled into containers through a 150 mesh screen.

In order to prepare a still lighter grade of the present transparent cutting oil, the foregoing finished cutting oil prepared from the light blend as described above can be cut back with additional pale oil to the desired extent, such as about 50% Obviously, many other modifications and variations of the invention as hereinbefore set forth may be made without departing from the spirit and scope thereof, and therefore, only such limitations should be imposed as are indicated in the appended claims.

I claim:

1. A transparent cutting oil consisting essentially of a mineral lubricating oil distillate having an SUS viscosity at 100 F. of 100 to 200 containing 0.4 to 0.95 percent by weight of added active free sulfur incorporated in the mineral oil at a temperature of about 290-340 F., and 0.75 to 5% by weight of sulfurized and chlorinated diisobutylene containing 23-25 percent of combined chlorine and 19-22 percent of combined sulfur, said sulfurized and chlorinated diisobutylene being non-corrosive to copper in the copper strip corrosion test, such as to produce no blackening of the copper strip at 122 F. for six hours, said cutting oil having a color on the Lovibond scale (/2 inch cell) below and a cutting effectiveness at least approaching that of a dark colored opaque more highly sulfurized heavy duty cutting oil.

2. A transparent cutting oil consisting essentially of a refined paraflin base mineral lubricating oil distillabe having an SUS viscosity at F. of 100-200 containing about 0.7-0.9% by weight of added active free sulfur incorporated in the mineral oil at a temperature of about 300-335 F., and about 125-2.0% by Weight of a sulfurized and chlorinated diisobutylene having 23-25% of combined chlorine and 19-22% of combined sulfur, said cutting oil having a color on the Lovibond scale (Vt inch cell) below 80.

References Cited in the file of this patent UNITED STATES PATENTS 2,291,404 Morway July 28, 1942 2,296,037 Kaufman Sept. 15, 1942 2,313,248 Lincoln et al. Mar. 9, 1943 2,318,629 Prutton May 11, 1493 OTHER REFERENCES Journal of the Inst. of Petroleum, April 1946, pp. 212-214. 

1. A TRANSPARENT CUTTING OIL CONSISTING ESSENTIALLY OF A MINERAL LUBRICATING OIL DISTILLATE HAVING AN SUS VISCOSITY AT 100*F. OF 100 TO 200 CONTAINING 0.4 TO 0.95 PERCENT BY WEIGHT OF ADDED ACTIVE FREE SULFUR INCORPORATED IN THE MINERAL OIL AT A TEMPERATURE OF ABOUT 290-340* F., AND 0.75 TO 5% BY WEIGHT OF SULFURIZED AND CHLORINATED DILSOBUTYLENE CONTAINING 23-25 PERCENT OF COMBINED CHLORINE AND 19-22 PERCENT OF COMBINED SULFUR, SAID SULFURIZED AND CHLORINATED DIISOBUTYLENE BEING NON-CORROSIVE TO COPPER IN THE COPPER STRIP CORROSION TEST, SUCH AS TO PRODUCE NO BLACKENING OF THE COPPER STRIP AT 122*F. FOR SIX HOURS, SAID CUTTING OIL HAVING A COLOR ON THE LOVIBOND SCALE (1/2 INCH CELL) BELOW 85 AND A CUTTING EFFECTIVENESS AT LEAST APPROACHING THAT OF A DARK COLORED OPAQUE MORE HIGHLY SULFURIZED HEAVY DUTY CUTTING OIL. 